Ambika,
I'm not sure I follow your question. Are you asking how to limit the range of the inputs or how to define a function that accepts x and y as two inputs?
If you want to limit the range, you will have to do it yourself inside the function to check that both x and y are within the range, and if not, throw an error.
If you just wanted to define the function, what you have should work. Although I would name the function something more intuitive (and relevant to what the function does, for instance addition) other than "data".
Cheers, -Venn
